Circuit-interrupter.



H. 6. MACDONALD- cmcun INTERRUPTER.

APPLICATION FILED FEB. 15- l9l2.

Ptnted July 4, 1916.

ATTORNEY WITNESSES: dwL/m UNITED STATES PATENT OFFICE.

HGWARD G. MACDONALD, OF WILKINSBURG, :PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMYANY, A CORPORATION OF PENNSYL-VANIA.

CIRCUITJNTERRUPTER.

Specification of Letters Eatent.

Patented July 4, 1916.

' Application filed February 15, 1912. Serial No. 677,865.

To all whom it may concern Be it known that I, HOWARD G. MACDON- ALB, acitizen of the United- States, and a resident of 'Wilkinsburg, in thecounty of.

Allegheny and State of Pennsylvania, have invented a new and usefulImprovement in Circuit-Interrupters, of which the following is aspecification.

My invention relates to circuit interrupters and it has specialreference to automatic tripping devices for this class of apparatus,

whereby the interrupters may be released erating conditions, such anarrangement opcrates satisfactorily. However, in certain cases Where itis found desirable to adjust the tripping mechanism to release theinterrupter at a predetermined low current, suflicient energy is notimparted to the electromagnet to overcome the frictional resistancebetween the heavy parts of the operating mechanism and the restraininglatch.

According to my present invention, 1 overcome the difficulty abovereferred to and accomplish a reliable and positive release of theinterrupter by means of an auxiliary power device which is normallyrestrained in its set position and which may be automatically releasedby the usual tripping magnet to forcibly actuate and release the mainlatch of the interrupter. Moreover, the relative proportions and thearrangement of parts is such that, althdughconsiderablc energy, which isavailable for tripping purposes, is stored in the power device, anexceedingly small amount of energy is re quired to eflect its release.

My invention may best be understood by reference to the accompanyingdrawing of which Figure 1 is a View, partially in side elevation andpartially in section, of a portion of a circuit interrupter. whichembodies my invention and Fig. 2 is a detail plan view of parts of theoperating mechanism cm bodied in my invention.

Referring to the drawing in detail, the device here shown comprises aplurality of stationary and movable contact members 1 and 2, anoperating mechanism 3 for the movable members 2, a latch 4 for saidoperating mechanism, an operating handle 5, an auxiliary power device 6and a tripping magnet 7.

The stationary contact members 1 are sup ported at the lower ends ofsuitable bushings 8, which are adapted to protect and insulate the mainconducting members (not shown) from the. casing or cover'9 of a tank 10in which the coiiperating contact members 1 and 2 are immersed in oil.The movable contact members2 are suitably supported upon a.cross arm32in the usual manner. said cross arm 3 being attached to the lower endof a rod 11. The coiiperating contact members 1 and 2 are preferably ofthe usual butt-contact type, although any other suitable constructionmay be employed.

The operating mechanism 3 comprises a lever 12, one end of which ispivotally connectedto the upper end of the rod 11 and the other end ofwhich is pivotally connected to the upper end of a guiding link 13, saidlink 13 being pivotally mounted upon a shaft 14.- which is carried by abracket member 15 pertaining to the cover 9. The link 13 projects ashort distance below its pivotal support 14 and is provided with a lugor projection 16, for a purpose to be hereinafter set forth.

A toggle for operating the movable con tact members 2 comprises a link17 which is pivotally connected to the lever 12 at a point substantiallymidway between its ends, and an arm 18 constituting an integral part ofa lever member 19 which is also mounted upon the shaft 14. A guidinglink 20, which is pivotally connected to the lever 12 and to the upperend of a standard 21, serves to constrain the movements of the operatingmechanism within prescribed limits.

Integrally associated with the lever 19 and its' arm 18, is a projectingmember 22 that is provided with an adjustable stop 23 to cooperate withthe projecting portion 16 of the link 13, whereby the pressurebetweenthe cooperating contact members 1 and 2 may be adjusted to any desiredvalue.

A lever 24 is fixed to the shaft- 14 and its a latch 27 is providedwhich is pivotally inountedupon a pin 28that is carried by a suitablebracketinember 29, and said latch 27 is provided with a cateh 3( )toengage a suitable detent 3'1 that'is secured to the lever 24,substantially midway between its ends.

Integrally associated with thelatch 27 ,is a promotion 32 having arecess 33 to receive a spring 34 which is disposed therein and actsagainst a flange 35 of the. supporting bracket 29 in order to maintainthe catch 30 in engagement with the detent' 31.

Furthermore, the-latch 27 is provided with an extension member 36 whichprojects he- -more fully set forth.

tween the respective-arms of a bifurcated portion 37 that is providedintermediate the ends of the lever 19. A pin 38 projects between thearms of the bifurcated portion 37 just referred to, and engages'theextension member 36 when the interrupter is closed. The extension member36 serves as a cam during the opening operation of the interrupter and,by reason-ofits peculiar shape and its engagement, with-the pin 38,therelease of the catch 'from the detent 31 is eflected when the. lever19 moves to its upper position, as will be hereinafter Theoperating'handlefi preferably located outside'of a casingi39 whichcnvelops and protects theoperating. mechanism 3 and the auxiliarypowerdevice '6, and is. rigidly Secured to the shaft. 14, while acounter weight-40 isrigidlj connected to said shaft by means of anarm40" to bring the operating handle 5 and thelever 24 to their upperpositions when the interrupter is released.

The auxiliary power device 6 comprises a bell crank lever 41 that ispivotally mounted upon a pin 42 and a coil spring'43, the

' ends of which are respectively connected to the upper end of an arm 44ofthe bell crank lever 42' and to a project ng member 45 whichconstitutes a part of the'supporting bracket 29. The free arm 46 of thebell crank lever 41 has a pin and slot connection 47 with a rod orstriking member 43 that is located beneath an arm 49 of the main latch 4and is adapted to actuate the same.-

The bell crank lever 41 is restrained in its setposition by means of alatch 50 having an arm 51 to be engaged by a striking member or rod 62that is associated with a movable core member 53 of the electromagnet 7,said magnet being also provided with a stationary core member 54 and anexciting winding or coil 55, in accordance with the usual practice.

It will be notedthat the main arm 44 of the bell crank lever 41'and thecoil spring 43 aredisposed approximately in a line, the one withtheother, so that the belle-rank lever 41 may be regarded as restrained ina prox'imatelyits dead center position ence, although considerableenergy may be stored in the-spring 43, the bell crank lever 41 may berestrained in its set position and released therefrom by an exceedinglysmall amount of energy. Manifestly, when the bell cranklever 41 and thespring 43 are released, the lever arm: through. which the spring 43acts, rapidly increasesso that the striking member 48 is projected withconsiderable force against the arm 49 of the latch 4, whereby a positiverelease of thelever 19 iseflected.

In order to reset theyauxiliziry power device 6 during the openingoperation of-the interrupter, a link56 is provided, the lower end ofwhich is pivotally'conuectedto the upper end of the bell crank lever 41,while the upper end thereof has a pinand slot-connection 57 with thelever 24. In order to permit of manualtripping of the interrupter, atripping rod 58, having. a handle or button 59, is provided, and is solocated with respect to the latch 27 that said latch may be manuallyoperated when desiredQ Assuming the. various parts of the interrupter tooccupy. the position shown, manual i release may be accomplished themanner hereinafter described;

-' The rod 58' isfirst .pus'lied i .ipwardly',". thereby engaging thelatch '27and'withdrawing the catch v30 from thedetei'it 31'. Thus, theoperatingmechanisiiiis released and the operating toggle, comprisingthelink '17 and the arm 18, is allowed to-collapse, there-'- bypermitting the separation. of the cooperating'contact members 1 and 2 byrealevers 19 and 24, which are still locked together by the latch 4', aswell as-the operating handle 5, are moved upwardlyin a clockwisedirection,"to their upper positions, as indicated in dot and dash lines.No move ment of the bell crank lever 41, however, is

effected during this operation. by reason of the lost-motion ,or'pin andslot connection 57 which has already been referred to. In

order to reset the interrupter, it is only' necessary to move thehandle-5 downwardly,

. thereby forcing the operatingtoggle, comprisingthe link 17 and the arm18, into its set position and thus raising the movable contact members 2into cobperative engagement with the stationary contact members 1. Whenthe associated levers 19 and 24 are in their lower positions, the latch27 again serves to restrain them, as hereiniiefore-set forth. H

Assuming that sullicient current traverses soil of the action ofgravity. During the .opening. operation of the interrupter, the

restraining said lover, a striking rod operntivoly assooiatwl. with thefree arm of said lever by a pin and slot connection for rolensing saidrestraining moans and electroresponsive means for releasing said latch.(3. ln a circuitintorrupter, the combination with cooperating stationaryand movnhlo oontuut members, an oporuting mechanism for said movableInclllbfir embodying tam pivotally nlonntotl relatively movableopvrnting lovers, and means for iPStl'fllIliDg' mid. operatingiliflliRIliSIil, of a pivotally mounted l'wl crank m'or illnt; gm-mmwith one of the arms thereof for actuating said lever, a latch forrestraining said lever, a striking rod operntivel) connected to the freearm of said lever for releasing said restraining means, andelectro-responsive moans for releasing said latch.

In testimony whereof, I have hereunto subscribed my name this 13th dayof Feb. 1912.

HOV/ARI) G. MACDONALD.

Witnesses D. H. MACE, B. B. Hmns.

